KR20010030210A - Non-oriented magnetic steel sheet having low iron loss and high magnetic flux density and manufacturing method thereof - Google Patents

Abstract

PURPOSE: To obtain excellent magnetic characteristics and superior workability by providing a composition containing specific amounts of Si and also containing C, S, N, O and B in amounts made to specific values or below, respectively, specifying average crystal grain size, and regulating the area ratio of such crystal grains that have crystal face orientation within specific angle with respect to the <111> axis at the surface of a steel sheet to a specific percentage or below. CONSTITUTION: The non-oriented silicon steel sheet has a composition containing, by weight, 2.0-4.0% Si and containing C, S, N, O and B in amounts made to less than 50 ppm respectively and also has 50-500 μm average grain size, and further, the area ratio of grains having crystal face orientation within 15°with respect to the <111> axis at the steel-sheet surface is regulated to less than 20%. This steel sheet can be manufactured by forming a molten steel of this composition into slab, hot rolling the slab, carrying out hot rolled plate annealing if necessary, cold rolling the resultant place once or cold rolling it two or more times while performing process annealing between cold rolling steps to finish it into final sheet thickness, and then applying recrystallization annealing to the resultant sheet.

Description

Non-oriented electrical steel sheet with low iron loss and high magnetic flux density and its manufacturing method {NON-ORIENTED MAGNETIC STEEL SHEET HAVING LOW IRON LOSS AND HIGH MAGNETIC FLUX DENSITY AND MANUFACTURING METHOD THEREOF}

The present invention relates to a non-oriented electrical steel sheet mainly used in the iron core material of electrical equipment and a method of manufacturing the same.

In recent years, in the movement of energy saving which is represented by electric power in the world, high efficiency of electric equipment is urgently desired. In addition, due to the miniaturization of electrical equipment, miniaturization of iron cores is also desired. In order to answer these demands, the non-oriented electrical steel sheet which is an iron core material of an electric machine is required to be low iron loss and high efficiency.

Conventionally, in order to reduce the iron loss of a non-oriented electrical steel sheet, the method of raising content of Si, Al, Mn, etc. has been generally used. This technique aims to reduce the eddy current loss by increasing the electrical resistance of the steel sheet. However, this method increases the nonmagnetic components, and therefore, there is a problem that a decrease in the magnetic flux density cannot be avoided.

Moreover, the method of not only simply increasing content of Si or Al but also increasing alloying components, such as C, S reduction, B addition, or Ni addition, is also known. B addition is disclosed in Japanese Laid-Open Patent Publication No. 58-15143. Ni addition is disclosed in Japanese Patent Laid-Open No. 3-281758. As a method of adding these alloy components, iron loss is improved, but the effect of improving the magnetic flux density is small. In addition, with these methods, the hardness of the steel sheet increases with the addition of alloys, resulting in deterioration of workability. That is, a non-oriented electromagnetic steel sheet may be processed and may not be used for an electrical apparatus. Therefore, the use was extremely limited and its versatility was inferior.

In addition, a method of changing the manufacturing process to improve the degree of orientation accumulation (steel sheet assembly structure) of the crystal grains constituting the steel sheet and to improve the magnetic properties is also known. For example, Japanese Unexamined Patent Publication No. 58-181822 discloses that a steel containing 2.8 to 4.0 mass% of Si and 0.3 to 2.0 mass% of Al is warm-rolled in a temperature range of 200 to 500 ° C, and {100 } <UVW> A method of developing azimuth is disclosed. In Japanese Laid-Open Patent Publication No. 3-294422, after hot-rolling a steel containing Si: 1.5 to 4.0 mass% and Al: 0.1 to 2.0 mass%, hot rolled sheet annealing of 1000 ° C to 1200 ° C is performed. And rolling reduction: 80 to 90% of cold rolling, and the method of developing a {100} <UVW> orientation is disclosed. However, the improvement of the magnetic properties by these methods is not remarkable. For example, in Example 2 of JP-A-58-181822, the magnetic flux density of a product plate containing 3.40 mass% of Si and 0.60 mass% of Al, and having a sheet thickness of 0.35 mm, has a B ₅₀ of 1.70 T and an iron loss. W _15/50 was 2.1 W / kg. In Japanese Patent Laid-Open No. 3-294422, the magnetic flux density of the product plate containing Si: 3.0 mass%, Al: 0.30 mass% and Mn: 0.20 mass%, and the sheet thickness of 0.50 mm is B ₅₀ to 1.71 T, and the iron loss is _It was 2.5 W / kg at W _15/50 .

In addition, proposals have been made to improve the manufacturing process. However, none of the proposals provided a sufficiently low iron loss and high magnetic flux density product.

The present invention aims to provide a non-oriented electrical steel sheet having excellent magnetic flux density and iron loss, which surpasses the magnetic properties obtained in the prior art, and a method of manufacturing the same.

MEANS TO SOLVE THE PROBLEM The present inventors earnestly examined the problem in the prior art in order to achieve low iron loss and high magnetic flux density simultaneously. And it came to develop a new non-oriented electrical steel sheet and its manufacturing method. That is, the summary structure of this invention is as follows.

In other words, the present invention comprises a composition containing 1.5 to 8.0 mass% of Si and 0.005 to 2.50 mass% of Mn, and suppressing the contents of C, S, N, O and B to 50 ppm or less, respectively. Crystal orientation parameter given in 1) is a non-oriented electromagnetic steel sheet having a low iron loss and a high magnetic flux density having a <Γ> of 0.200 or less.

… (One)

Here, (u _ij , v _ij , w _ij ) is 90 × i / (m in the rolling direction from the rolling direction toward the rolling perpendicular direction, where the crystal orientation is determined by crystal grains j represented by (hkl) <uvw>. -1) is the unit vector of the i th parallel to the inclined direction. (i = 1,2… m, j = 1,2… n, u _ij ² + v _ij ² + w _ij ² = 1) In addition, v _j is the area ratio of the crystal grains j with respect to all the measurement grains.

Moreover, it is preferable that the area ratio in the steel plate surface of the crystal grain whose average crystal grain diameter is 50-500 micrometers, and a crystal surface orientation is 15 degrees or less in the <111> axis is 20% or less. In addition, Al: 0.0010 to 0.10 mass% and <Γ> 0.195 or less, Sb: 0.01 to 0.50 mass%, or Ni: 0.01 to 3.50 mass%, Sn: 0.01 to 1.50 mass% , Cu: 0.01 to 1.50 mass%, P: 0.005 to 0.50 mass%, and Cr: 0.01 to 1.50 mass% are preferably contained at least one kind.

In the present invention, the molten steel of the component containing Si: 1.5 to 8.0 mass% and Mn: 0.005 to 2.50 mass% and suppressing the contents of S, N, O, and B to 50 ppm or less is used as the slab. The slab is hot rolled, and then hot rolled sheet annealing is carried out, followed by one or more cold rollings including intermediate annealing to finish the final plate thickness, and then recrystallization annealing, if necessary, an insulation coating. In the step of carrying out, the amount of C in the steel sheet is adjusted to 50 ppm or less in any of the steps during melting or before recrystallization annealing, the hot rolled sheet annealing is carried out at a temperature range of 800 to 1200 ° C, and then 800 to It is a manufacturing method of the non-oriented electrical steel sheet with low iron loss and high magnetic flux density which cools the temperature range of 400 degreeC to 5-80 degreeC / s. Moreover, it is preferable to perform recrystallization annealing by making temperature rise in the temperature range of 700 degreeC or more into 100 degreeC / h or less, and reaching to the temperature range of 750 degreeC or more and 1200 degrees C or less. Alternatively, the recrystallization annealing is performed at a temperature range of 500 to 700 ° C. or higher to 2 ° C./s or higher, and the temperature is raised to 700 ° C. or higher to complete recrystallization, and then cooled to a temperature range of 700 ° C. or lower, and then elevated again. It is preferable to carry out by carrying out at 100 degrees C / h or less in the temperature range of 700 degreeC or more, and reaching to the temperature range of 750 degreeC or more and 1200 degrees C or less. Moreover, it is also preferable to make the average crystal grain diameter before final cold rolling into 100 micrometers or more, and to carry out at least 1 pass of final cold rolling at the rolling temperature of 150-350 degreeC. The molten steel of the material is also Al: 0.0010 to 0.10 mass%, Sb: 0.01 to 0.50 mass%, or Ni: 0.01 to 3.50 mass%, Sn: 0.01 to 1.50 mass%, Cu: 0.01 to 1.50 mass%, P: It is preferable to contain at least one of 0.005 to 0.50 mass% and Cr: 0.01 to 1.50 mass%.

1 is a diagram for explaining vectors (u _ij , v _ij , w _ij ) required for the calculation of <Γ>.

2 is a diagram showing the effect of Al content on magnetic flux density and iron loss.

3 is a diagram illustrating Γ _ij in each direction of {100} &lt; 001 &gt; crystal grains.

Fig. 4 is a diagram showing the direction variations of B ₅₀ ^J , Γ (J) and I {100} / I {111} in each direction of the product plate.

5 is a view showing the relationship between the magnetic flux density of the product at each side of the plate (B ₅₀ ^J) and the Γ (J).

Fig. 6 is a graph showing the relationship between the magnetic flux density in the ring sample of the product plate and the average value &lt; Γ &gt; in the plane determined by the crystal grain orientation measurement.

Fig. 7 shows the relationship between the magnetic flux density and I {100} / I {111} in the ring sample of the product plate.

8 is a diagram showing the influence of the amount of material Al on the <Γ> of a product plate.

9 is a diagram showing the effect of cooling rate after hot-rolled sheet annealing on &lt; Γ &gt;

10 is a view showing the effect of recrystallization annealing conditions on the iron loss and magnetic flux density of the product plate.

Fig. 11 is a diagram showing the effect of recrystallization annealing conditions on <Γ> of a product plate.

12 is a diagram showing the effect of recrystallization annealing conditions on the product sheet grain size.

Fig. 13 is a graph showing the effect of P {111} of the product plate on the iron loss of the product plate.

14 is a graph showing the effect of cold rolling temperature on the iron loss and P {111} of the product plate.

15 is a graph showing the effect of the average particle diameter after hot-rolled sheet annealing on iron loss and P {111} of the product sheet.

MEANS TO SOLVE THE PROBLEM The present inventors earnestly examined in order to overcome the limitation of the prior art with respect to the improvement of the magnetic characteristic of the conventional high Si non-oriented electrical steel sheet. As a result, it was found that the magnetic properties can be significantly improved by appropriately controlling the orientation of the crystal grains constituting the steel sheet. In particular, it has been newly found that it is advantageous to use <Γ> as an index of the crystal orientation control. In addition, the hot-rolled sheet annealing conditions and the recrystallization annealing conditions for refining the adequacy of <Γ> were examined, and particularly advantageous conditions were newly discovered.

Here, the crystal orientation parameter <Γ> determined by Formula (1) can be specifically calculated | required by the following method.

First, the orientation of individual crystal grains on the rolled steel sheet is measured using an Electron Back Scattering Pattern (hereinafter referred to as EBSP). Crystal grain orientation is represented by (hkl) <uvw>. Here, (hkl) is a display of the Miller index of the steel sheet rolling surface in the measurement crystal grain. Further, the vector (u, v, w) is parallel to the rolling direction of the measurement crystal grains.

The unit vectors u _ij , v _ij , w _{ij in} the i-th direction between the rolling direction in the rolling direction in the steel sheet rolling surface in each crystal grain j can be obtained as shown in FIG. 1. When the orientation of crystal grains j is (hkl) <uvw>, (u _lj , v _lj , w _lj ) is the unit vector in the rolling direction: (u, v, w) / (u ² + v ² + w ² ) (u _mj , v _mj , w _mj ) corresponds to the unit vector in the rolling perpendicular direction.

Next, Γ _ij is calculated according to (2).

Γ _ij = u _ij ² v _ij ² + v _ij ² w _ij ² + w _ij ² u _ij ² . (2)

It is preferable to calculate Γ _ij in each of the crystal grains in at least 15 ° directions, that is, in seven directions in the range from the rolling direction to the rolling right angle direction. Based on Γ _ij for each direction in the rolling surface of each crystal grain thus obtained, the in-plane average ( )

In addition, what was weighted average by the area ratio (V _j ) about the n crystal grains measured is set to <Γ>.

In other words,

And in order to obtain a statistically significant value, it is preferable to measure about 1000 or more crystal grain orientation.

Γ _ij that determines this <Γ> becomes an intrinsic value in the crystal direction. For example, the result of having calculated Γ _ij in each direction with respect to the {100} <001> crystal grain which is a positive cube orientation is shown in FIG. Since the unit vector in the rolling direction in the regular cube orientation crystal grains is (0,0,1), Γ _ij = 0. Since the unit vector in the rolling direction is (0,1,0), Γ _ij = 0. The unit vector in the direction tilted at 45 ° from the rolling direction is Since (0,1,1), Γ _ij = 0.25 and the maximum value is taken.

In addition, <Γ> can also be calculated | required by calculating an azimuth distribution function (ODF) from the pole figure measured by X-ray diffraction. That is, in the result of this ODF, the volume fraction of the crystal grain which has the crystal surface of a specific Miller index can be calculated with respect to the specific direction of a steel plate. When the volume fraction is applied as the occupancy ratio, multiply the volume fraction by Γ _ij determined from the Miller index, add this value to each Miller index, and calculate the value for each direction from the in-plane rolling direction to the rolling rectangular direction. This becomes <Γ>.

Hereinafter, the experimental result which led to this invention is explained in full detail.

First, experiments were conducted on the effects of Al and Sb. Ingot group (A) contains 3.5 mass% of Si and 0.10 mass% of Mn, reduces C, S, N, O and B to 20 ppm or less, respectively, and variously changes the amount of Al contained. Solvent Ingot group (B) added Sb: 0.04 mass% in addition to ingot group (A), and was solvent. These ingots were heated to 1040 ° C. and finished to a thickness of 2.3 mm by hot rolling. The hot rolled sheet was subjected to hot rolled sheet annealing at 1075 ° C for 5 minutes, and then cooled between 20 ° C and s between 800 and 400 ° C. In addition, the hot-rolled annealing plate was pickled and cold-rolled at a temperature of 250 ° C. to finish with a final plate thickness of 0.35 mm. The cold rolled sheet was heated to 12 ° C / s between 500 ° C and 700 ° C, recrystallized annealing was performed at 1050 ° C for 10 minutes, to obtain a product plate. Ring-shaped test pieces having an inner diameter of 100 mm and an outer diameter of 150 mm were collected from these products, and the magnetic flux density of each steel plate: B ₅₀ (T) and iron loss: W _15/50 (W / kg) were measured.

In FIG. 2, the influence of Al content of the raw material on the magnetic flux density and iron loss of a product board is shown. As shown in Fig. 2, the magnetic properties vary greatly by the Al content of the material. A good value of B ₅₀ of 1.68 T or more and W _15/50 of 2.1 W / kg or less in an Al range of 0.0010 mass% to 0.10 mass% is obtained. In particular, in the range of 0.005 mass% to 0.020 mass% of Al, very excellent values of B ₅₀ of 1.70 T or more and W _15/50 of 1.9 W / kg or less are obtained. In addition, in the ingot group (B) to which Sb was added, the remarkable improvement of the magnetic characteristic was recognized.

In this experiment, to find out why excellent magnetic properties were obtained, the grain size of each product plate was also examined. Usually, in the non-oriented electrical steel sheet, iron loss improves when the grain size of a product board coarsens. The grain size depends on the grain growth behavior during recrystallization annealing. In this experiment, the influence of the amount of material Al and the addition of Sb on the grain size of the product sheet was small, and the grain size was 200 to 300 µm in any steel sheet. In other words, the magnetic properties and the grain growth behavior during recrystallization annealing were almost irrelevant.

Therefore, it is considered that the improvement of the magnetic properties in the range of 0.0010 to 0.10 mass% and the further improvement of the magnetic properties by the addition of Sb are due to the improvement of the crystal orientation. Thus, the crystal grain orientation of the product plate is measured by EBSP. And the orientation of about 2000 crystal grains in the 10 mm x 10 mm angle area | region of the steel plate surface was measured.

Here, the inventors analyzed using the above-mentioned <Γ> newly created. As a result, it was newly found that there is a very strong correlation between <Γ> and magnetic flux density.

First, on the basis of the measurement results of about 2000 crystal grain orientations in the product sheet, the Γ _ij defined in Eq. (2) is calculated in the direction J (for example, rolling direction) of interest, and weighted averaged over the area of the grain. Let it be Γ (J). As a result of investigating the relationship between Γ (J) and the magnetic flux density in the direction J of the product plate, a new correlation was found. In addition, the intensity ratio I {100} of {111} plane intensity (hereinafter referred to as I {111}) and {100} plane intensity (hereinafter referred to as I {100}) by X-ray diffraction which has been conventionally used as a comparison. } / I {111} was also investigated. Moreover, I {100} / I {111} is the evaluation method of the aggregate structure disclosed by Unexamined-Japanese-Patent No. 8-134606.

First, the magnetic flux density (B ₅₀ ^J ) in each direction between the rolling direction (0 °) and the rolling perpendicular direction (90 °) of the product sheet having the amount of Al belonging to the ingot group A in 0.01 mass% was investigated. It was. The irradiation cut out the Epstein sample from the direction of every 15 degrees between the rolling direction (0 degree) and the rolling perpendicular direction (90 degree), and measured magnetically. 4 shows the direction change of B ₅₀ ^J and Γ (J). As shown, B ₅₀ ^J and Γ (J) in Fig. 4 by the variation in each direction. Also in Figure 5, it shows the relationship between the B ₅₀ ^J and Γ (J). As shown in FIG. 5, it can be seen that there is a strong correlation between B ₅₀ ^J and Γ (J).

4 also shows the value of I {100} / I {111}. Since the value of I {100} / I {111} reflects the surface strength, as shown in FIG. 4, it was confirmed that the value in each direction of the measurement sample was almost constant, and the change of the magnetic flux density was not reflected.

Subsequently, crystal grain orientation measurement and X-ray diffraction were performed on the product plates of each ingot group, and the measurement result of the magnetic flux density in the ring sample, the average value of Γ (J) in the rolling surface, and I {100} / I The relationship of {111} was investigated. In addition, the average of Γ (J) in the plane: <Γ> represents Γ (J) in each direction by 15 ° from the rolling direction (0 °) to the rolling perpendicular direction (90 °) in each crystal orientation. Calculate using the measurement result and set it as the average value.

Fig. 6 shows the relationship between the magnetic flux density in the ring sample of the product plate and the average value <Γ> in the plane obtained from the crystal grain orientation measurement. Strong correlation was recognized for both. It was found that <Γ> should be 0.200 or less in order to obtain a high magnetic flux density of B ₅₀ > 1.65 T. On the other hand, Fig. 7 shows the relationship between the magnetic flux density in the ring sample of I {100} / I {111} and the product plate irradiated using the same sample. There is no clear relationship between the two. It is not clear why these results were obtained, but it is estimated as follows. In the method for evaluating I {111} / I {100}, the strength of only the crystal grains of a very small part of the crystal plane near {111} or {100} is evaluated. That is, the contribution of the strength of the crystal grains of a relatively important crystal plane other than these, for example, {544}, {221}, {332} to the magnetic properties is excluded from the evaluation range. On the other hand, in the evaluation method by this invention, Γ (J) in each direction of a steel plate is calculated | required directly from the orientation of each crystal grain, and the in-plane average value is computed from these values. That is, it is estimated that not excluding the crystal grains having an important crystal plane yielded good results.

There is another advantage of using <Γ>. Generally, the saturation magnetic flux density of a steel sheet changes with content of elements other than iron. Thus, even if the product plate has the orientation concentration degree of the same crystal grain, for example, the value of the magnetic flux density changes. Therefore, when comparing the orientation density | concentration of products of the component system from which a component differs, it cannot simply compare with the value of magnetic flux density. However, since <Γ> is determined as the crystal orientation itself, it is possible to evaluate the integrated state of the crystal grain orientation of the product sheet regardless of the alloy composition. As such, <Γ> is a very valid indicator.

Next, the result of having examined the relationship between Al content and an impurity amount is described.

Ingot group (B) (within the invention), containing 3.5% by mass of Si, 0.10% by mass of Mn and 0.03% by mass of Sb, and reducing C, S, N, O and B to 50 ppm or less, respectively. And the ingot which changed the amount of Al variously was dissolved. In addition, ingot group (C) (outside the invention) includes Si: 3.5 mass% and Mn: 0.12 mass%, and each content of C, S, N, O and B is 50 ppm or more, and the total amount thereof is also The steel ingot was 350 ppm or more and the amount of Al was varied. These ingots were heated to 1100 ° C. and finished to a thickness of 2.4 mm by hot rolling. Subsequently, hot-rolled sheet annealing was performed for 1100 ° C x 5 minutes, and among them, 800 to 400 ° C was cooled at 15 ° C / s. Furthermore, these annealing plates were pickled and finished by cold rolling at 200 ° C. to a final plate thickness of 0.35 mm. These cold rolled sheets were subjected to recrystallization annealing at 1050 ° C for 10 minutes to give a product sheet. The crystal grain orientation of the product sheet thus obtained was measured by EBSP with respect to about 2000 crystal grains in an area of 10 mm x 10 mm angle on the steel plate surface. From this result, the average value <Γ> in the rolling surface was calculated | required.

8, the relationship between Al content and <Γ> in each ingot group is shown. In the ingot group (B) which reduced impurity elements C, S, N, O, and B, <Γ> is 0.200 or less. However, in the ingot group (C) containing many impurity elements C, S, N, O and B, <Γ> exceeds 0.200. In addition, in the ingot group (B), when the amount of Al is in the range of 10 to 1000 ppm, <Γ> is 0.195 or less, and it is particularly advantageous to improve the magnetic flux density.

Based on this experiment, more polite research was conducted. As a result, <Γ> is 0.195 or less, and in order to obtain particularly good texture, which is advantageous for improving the magnetic flux density, not only the Al content is controlled but also the impurity elements C, S, N, O and B are 50 ppm or less, respectively. It was found that reducing is essential.

On the other hand, in the conventional high-quality non-oriented electromagnetic steel sheet having a high amount of Si, a method of increasing the intrinsic electrical resistance has been adopted for iron loss improvement. This method of increasing the high electric resistance also has the effect of promoting grain growth of crystal grains. This is for coagulation coarsening of AIN, which is a precipitate in the steel that suppresses crystal grain growth. In order to acquire the effect which suppresses this crystal grain growth, it is necessary to ensure content of Al or more. Conventionally, content of Al is regulated by the quantity exceeding at least 0.1 mass%, and it is usually content of about 0.4-1.0 mass%. However, in the results obtained by the experiments of the inventors, the aggregates most preferably developed in the range of 0.0010 to 0.10 mass%. As a result, <Γ> became 0.195 or less, showing the best values of both magnetic flux density and iron loss. This Al range is much lower than that of the prior art.

In this way, it was found that the impurity elements C, S, N, O, and B in the material component were reduced to 50 ppm or less, respectively, and the good aggregate structure with low <Γ> was developed by suppressing the Al content. The reason for this is not always clear, but the inventors consider that the grain boundary shift is related to the suppression of impurities. That is, first, by increasing the purity of the raw material, the influence of the impurity element is eliminated, and grain boundary movement becomes easy. Even if it is an impurity element, this effect is remarkable when it reduces especially with respect to C, S, N, O, and B which have a strong grain boundary segmentation tendency. In addition, by reducing Al to 0.10 mass% or less, the arrangement state of crystal lattice closer to pure iron becomes closer. In this case, the original mechanism that the grain boundary moving speed difference depends on the grain boundary structure becomes remarkable. In other words, in the grain growth process by recrystallization, only some grain boundaries move preferentially depending on the aggregate structure. As a result, the growth of a large number of crystal grains having magnetically disadvantageous crystal faces such as {111}, {554}, {321} and the like is suppressed. In other words, a change in texture occurs in the direction of decreasing <Γ>, and the magnetic properties are improved.

Regarding the addition of Sb, it is recognized that the crystal orientation having a near plane of {100} favoring the magnetic properties at the time of recrystallization nucleation is preferentially recrystallized. By combining with the Al reduction effect, it is estimated that the magnetic characteristics greatly improve.

In addition, when Al is less than 10 ppm, the effect of improving the magnetic properties by reducing the impurity elements C, S, N, O and B is reduced. In this case, it is observed that coarse silicon nitride is formed in the steel. The silicon nitride is expected to change the deformation behavior during cold rolling. As a result, it is estimated that <Γ> in the structure after recrystallization annealing increases somewhat. Therefore, <Γ> decreases due to impurity element reduction, but as a result, the improvement in magnetic properties is considered to be small. On the other hand, when Al amount is contained 10 ppm or more, formation of this coarse silicon nitride is suppressed. Therefore, it is possible to avoid an increase in &lt; Γ &gt; due to the above-described change in deformation behavior during cold rolling. That is, the reduction of impurity elements C, S, N, O and B when the Al content is 10 ppm or more is particularly advantageous for the improvement of the magnetic properties.

Thus, in order to make <Γ> 0.200 or less, it is important to make impurity elements C, S, N, O, and B into 50 ppm or less, respectively. Further, by suppressing the Al content to 0.001 to 0.10 mass% and containing a predetermined amount of Sb as needed, &lt; Γ &gt; can be reduced to 0.195 or less, and the magnetic properties can be further improved.

In addition, the method of improving the aggregate structure and improving the magnetic properties without adding a large amount of Al of the present invention has an advantage of high saturation magnetic flux density because the amount of alloying elements is small. In addition, since the increase in hardness is avoided and the workability of the product is secured, there is also an advantage that the application to general-purpose electrical appliances is promoted.

In addition, an experiment was conducted on the hot-rolled sheet annealing conditions in order to establish a method separate from the component adjustment, which makes it possible to improve the texture and allow the <Γ> value to be 0.200 or less.

The steel ingot which contained 3.6 mass% of Si, 0.13 mass% of Mn, 0.009 mass% of Al, and 0.06 mass% of Sb, and reduced C, S, N, O, and B to 20 ppm or less, respectively, was dissolved. This ingot was heated to 1120 ° C, and finished to 2.8 mm by hot rolling. Subsequently, hot-rolled sheet annealing was performed at 1100 ° C. for 5 minutes, and then cooling was performed by variously changing the cooling rate. Furthermore, these annealing plates were pickled and finished by cold rolling at 230 ° C. to a final plate thickness of 0.50 mm. The cold rolled sheet was subjected to recrystallization annealing at 1070 ° C x 10 seconds to obtain a product sheet. In the product sheet thus obtained, ring test pieces having an inner diameter of 100 mm and an outer diameter of 150 mm were collected, and the magnetic flux density and iron loss of each steel sheet were measured. In addition, the crystal grain orientation of the product sheet was measured for about 2000 crystal grains in an area of 10 mm x 10 mm angle on the surface of the steel sheet by EBSP. <Γ> was calculated from the results.

9 shows the relationship between the cooling rate in the temperature range of 800 to 400 ° C. after the hot rolled sheet annealing and <Γ>. By setting the cooling rate in the range of 5 to 80 ° C / s, it can be seen that an especially good texture of <Γ> of 0.195 or less can be obtained. By regulating the cooling rate, the dispersion state of AlN precipitates present in trace amounts becomes coarse. As a result, it is estimated that nonuniform deformation at the time of cold rolling is promoted, and recrystallization structure is improved. However, the essential mechanism of collective improvement is not clear.

Next, as a requirement for further improving the iron loss and the magnetic flux density, the following experiment was conducted to investigate the recrystallization annealing conditions.

As the ingot D, a steel ingot containing 3.6 mass% of Si, 0.13 mass% of Mn, and 0.30 mass% of Al, and having reduced C, S, N, O, and B to 20 ppm or less, respectively, was dissolved. In addition, the steel ingot E contained 3.6 mass% of Si, 0.13 mass% of Mn, 0.009 mass% of Al, and 0.06 mass% of Sb, and reduced C, S, N, O, and B to 20 ppm or less, respectively. One ingot was dissolved. Each ingot was heated to 1070 ° C. and finished to a thickness of 2.5 mm by hot rolling. The hot rolled sheet was subjected to hot rolled sheet annealing at 1170 ° C. for 5 minutes, and then cooled between 800 ° C. and 400 ° C. at 10 ° C./s. These annealing plates were pickled and cold-rolled at 200 ° C. to finish at a final plate thickness of 0.35 mm. A sample was taken from the cold rolled plate, and recrystallization annealing was carried out separately under the following three conditions to obtain a product plate.

[Annealing 1]

Temperature rising rate: 30 ℃ / s average between 500 ℃ at room temperature

15 ° C / s on average between 500 and 700 ° C

8 ° C / s, averaged between 700 and 900 ° C

Cracking condition: 900 ℃ × 10 seconds

Cooling rate: average 10 ℃ / s from crack to room temperature

Annealing atmosphere: hydrogen 50%, nitrogen 50%, dew point -30 ℃

[Annealing 2]

Temperature rising rate: 100 ℃ / h average between 500 ℃ at room temperature

50 ° C / h between 500 and 900 ° C

Cracking condition: 900 ℃ × 10 hours

Cooling rate: 100 ℃ / h on average from crack to room temperature

Annealing atmosphere: Ar dew point -30 ℃

[Annealed 3]

After annealing 1 is performed, annealing 2 is performed.

Ring test pieces having an inner diameter of 100 mm and an outer diameter of 150 mm were taken from each product plate, and the magnetic flux density and iron loss of each test piece were measured. The crystal grain orientation of the product sheet was measured by EBSP with respect to approximately 2000 crystal grains in the 10 mm x 10 mm square region of the steel plate surface to obtain <Γ>.

10 shows the relationship between the recrystallization annealing conditions and the magnetic properties. 11 shows the relationship between the recrystallization annealing condition and <Γ>.

As for the iron loss, the steel sheet which had undergone annealing 2 was better than any steel ingot. In addition, iron loss of the steel sheet subjected to the annealing 3 was better than that of the steel sheet subjected to the annealing 1 and the annealing 2. Moreover, iron loss is favorable compared with the steel ingot (E) which added Sb no addition.

On the other hand, about the magnetic flux density, in the ingot (E) which added Al and Sb, the annealing 2 and the annealing 3 improved compared with the annealing 1. However, there was no change in the steel ingot (D) which does not contain Sb and contains 0.3 mass% of Al. As for <Γ>, a change corresponding to a change in magnetic flux density is shown. In the steel ingot E, the lowest <Γ> and the high magnetic flux density were obtained.

12 shows the relationship between the particle size after recrystallization annealing and the recrystallization annealing conditions. As shown in Fig. 12, the grain growth proceeded slightly, compared to the annealing 1, which is a rapid heating, but annealing 2, which is a slow heating. In addition, in each annealing condition, the maximum reaching temperature is the same as 900 ° C. Moreover, in the annealing 3 which performed complete | heating after rapid heating, particle growth advanced compared with annealing 1 and 2. Particularly, grain growth was remarkable in the steel ingot (E). In the annealing 2, although the annealing 1 which is a sudden heat is the same as reached temperature, since a crack time differs, it is thought that particle growth advanced. Moreover, about annealing 3, the particle size is remarkably increasing compared with annealing 2. As shown in FIG. Annealing 3 is thermally effective despite being slightly different from annealing 2. When the annealing 2 and the annealing 3 are compared, the temperature increase rate at the time of recrystallization nucleation is different. Therefore, it is estimated that the difference in recrystallized texture based on the difference in the texture formation process caused by this difference greatly changed the subsequent grain growth behavior. However, the essential mechanism is not clear.

Moreover, the addition element of the raw material was also examined. As a result, it was found that the magnetic flux density of the product is improved by adding Ni. It is estimated that Ni is a ferromagnetic element for some reason to improve the magnetic flux density. However, the detailed reason is not clear. Moreover, the tendency which iron loss improves by addition of Sn, Cu, P, and Cr was recognized. It is estimated that iron loss was reduced by increasing the dielectric constant.

In particular, it has been found that, with regard to iron loss improvement, it is effective to optimize the area ratio of crystal grains (hereinafter referred to as P (111)) whose crystal plane orientation is within 15 degrees from the <111> axis. It demonstrates concretely below.

A steel ingot containing Al in various ranges was dissolved in a steel containing 2.5 wt% of Si and 0.12 wt% of Mn and having reduced C, S, N, O and B to 20 ppm or less, respectively. Subsequently, these ingots were heated to 1100 ° C., and hot rolled sheets were formed into hot rolled plates having a thickness of 2.4 mm. The hot rolled sheet was subjected to hot rolled sheet annealing for 1175 ° C × 2 minutes, pickled, and finished with cold rolled sheet having a final plate thickness of 0.35 mm by cold rolling at 250 ° C. The cold-rolled sheet was subjected to recrystallization annealing for 1100 ° C. for 5 minutes to obtain a product plate. By varying Al, a product having a different crystal orientation can be obtained.

Epstein test pieces of the size of 30 x 280 mm were taken from the product plate in the rolling direction (L direction) and the rolling right direction (C direction), and the average magnetic flux densities and iron losses in the L and C directions were measured. Moreover, the crystal grain orientation of the product board was measured by EBSP. The measurement was performed for about 2000 crystal grains in a 10 mm x 10 mm angle region of the steel plate surface.

About the measurement result, the minimum angle difference between each crystal plane orientation and <111> axes was analyzed. As a result, it was found that there is a strong correlation between the area ratio (hereinafter referred to as P {111}) and the magnetic properties of the crystal grains whose crystal plane orientation is within 15 degrees from the <111> axis.

13 shows the relationship between the iron loss value of the product plate and P {111}. As shown in Fig. 13, there was a strong correlation between the iron loss of the product plate and P {111}. In particular, it turned out that favorable iron loss ( _W15 / ₅₀ <= _2.20W / kg) is obtained by making P {111} 20% or less. The reason for this is that in the calculation of P {111}, the allowable range is widened to 15 °, so that many orientations other than {111} such as {544}, {554}, {221}, {332}, etc. It is assumed that the contribution to the magnetic properties of the crystal grains is also evaluated.

In addition, in order to clarify the influence on the magnetic properties of the aggregate, the following experiment was conducted.

The steel ingot which contained 2.6 wt% of Si, 0.13 wt% of Mn, and 0.009 wt% of Al, and reduced C, S, N, O, and B to 20 ppm or less, respectively, was dissolved. This steel ingot was heated to 1050 ° C. to obtain a 2.6 mm thick hot rolled sheet by hot rolling. The hot rolled sheet was annealed at 1150 ° C for 3 minutes. The annealing plate was pickled and then cold rolled at various temperatures in the range of 400 ° C. at room temperature, and finished with a final plate thickness of 0.35 mm. The cold rolled sheet was subjected to recrystallization annealing at 1050 ° C for 10 minutes to obtain a product plate.

An Epstein test piece of 30 x 280 mm size was taken from the obtained product plate in the L direction and the C direction, and the average magnetic flux density and iron loss in the L and C directions of the respective steel sheets were measured.

The crystal grain orientation of the product sheet was measured by EBSP with respect to about 2000 crystal grains in the 10 mm x 10 mm angle region of the steel plate surface, to obtain P {111}.

14A and 14B show the relationship between the rolling temperature, iron loss and P {111}. As shown in FIG. 14, by suppressing rolling temperature in the range of 150-350 degreeC, the value of P {111} became a low value and the outstanding iron loss was obtained.

Next, the experiment which performed the same process except having changed the hot-rolled sheet annealing temperature variously using the ingot of the same component was performed.

15A and 15B show the results obtained by examining the relationship between the average particle diameter (D) after hot-rolled sheet annealing, the iron loss characteristics of the product plate, and P {111}. As shown in Fig. 15, by making the average particle diameter after hot-rolled sheet annealing, that is, the average particle diameter before final cold rolling, to 100 µm or more, it became clear that P {111} significantly decreased, and the iron loss characteristics were further improved.

Hereinafter, the reason for limitation of each structural requirement of this invention is demonstrated.

As a component of the electromagnetic steel sheet of this invention, it is necessary to contain Si, to increase an electrical resistance, and to reduce iron loss. For that, more than 1.5 mass% Si is required. On the other hand, when it exceeds 8.0 mass%, the magnetic flux density will fall and the secondary workability of a product will also deteriorate remarkably. Therefore, Si content is restrict | limited to 1.5-8.0 mass%.

Mn is a component necessary for making hot workability favorable. Less than 0.005 mass%, the effect is weak. On the other hand, when it exceeds 2.50 mass%, the saturation magnetic flux density decreases. Thus, the range is 0.005 to 2.50 mass%.

Moreover, in order to realize the crystal orientation aimed at by this invention, it is essential to reduce the trace component of a steel plate. That is, in the whole steel sheet except the coating of the steel plate surface, the content of C, S, N, O and B needs to be 50 ppm or less, preferably 20 ppm or less, respectively. At a content higher than this, <Γ> in the crystal orientation of the product increases, and the iron loss increases.

Next, in this invention, control of crystal orientation is essential. In other words, in order to obtain good magnetic properties, it is important that the average value <Γ> in the rolling surface of Γ determined by Equation (1) is 0.200 or less. The reason is as described above.

Moreover, it is preferable that the average grain size of a product board shall be 50-500 micrometers. This is because hysteresis loss increases when the average grain size is less than 50 µm. Therefore, deterioration of iron loss cannot be avoided even by the application of the present invention. Moreover, since the hardness of a product plate increases, workability also deteriorates. On the other hand, when it exceeds 500 micrometers, the increase of eddy current loss is very severe. Therefore, deterioration of iron loss cannot be avoided even by the application of the present invention.

Moreover, in order to obtain favorable iron loss, it is preferable to make P {111} 20% or less. This is because, when P {111} exceeds 20%, both the magnetic flux density and the iron loss of the product deteriorate significantly.

And in order to ensure favorable blanking property, it is preferable that Vickers hardness is 240 or less. Various methods can be considered as a method of achieving this, but the method mainly by adjusting the amount of components, such as Si, Al, Mn, is advantageous.

Next, the manufacturing method of the electromagnetic steel sheet of this invention is explained in full detail.

First, as the molten steel component, the reason for regulating Si to 1.5 to 8.0 mass% and Mn to 0.005 to 2.50 mass% is as described above.

Next, it is essential to regulate the upper limit of the impurity elements of C, S, N, O and B as 50 ppm, preferably 20 ppm, respectively. And with respect to C, it is essential to set it as 50 ppm or less at least before recrystallization annealing. For this purpose, if it is 50 ppm or less in the molten steel component stage or exceeds 50 ppm in the molten steel stage, what is necessary is just to make it 50 ppm or less by the decarburization process in an intermediate process. When the content of these impurities exceeds 50 ppm, the value of <Γ> after recrystallization annealing increases and the magnetic properties deteriorate. This is considered to be because selective movement of special grain boundaries is hindered.

In addition, Al amount control is the most advantageous technique for obtaining the non-oriented electromagnetic steel sheet whose <Γ> of this invention is 0.200 or less. In particular, in order to obtain a good product having an aggregate structure having a <Γ> of 0.195 or less, it is preferable that Al be in a range of 0.0010 to 0.10 mass%. When Al exceeds 0.10 mass%, the texture changes, so that <Γ> in the plate increases, and iron loss and magnetic flux density deteriorate. On the other hand, when Al is less than 0.0010 mass%, silicon nitride precipitates, affecting the deformation behavior during rolling. As a result, the aggregate structure changes to increase <Γ>, and the effect of reducing <Γ> due to the reduction of impurity elements C, S, N, O and B is reduced. Therefore, Al should be 0.0010 mass% or more, and it is advantageous for improvement of iron loss and magnetic flux density.

In addition to the above method by component adjustment, conditional control of the hot-rolled sheet annealing is advantageous for obtaining a good aggregate structure in which &lt; Γ &gt; As this condition, annealing is performed in the temperature range of 800-1200 degreeC, and the temperature range of 800-400 degreeC among them is cooled to 5-80 degreeC / s.

If the hot rolled sheet annealing temperature is lower than 800 ° C., the recrystallization of the hot rolled sheet becomes insufficient, and the improvement of the magnetic properties is also insufficient. On the other hand, when the hot rolled sheet annealing temperature exceeds 1200 ° C., the grain size of the hot rolled sheet becomes excessively coarse, and cracks occur during cold rolling. Therefore, it is preferable that hot-rolled sheet annealing temperature shall be 800-1200 degreeC. The cooling rate is as described above.

In addition, recrystallization nucleation behavior can be changed by additionally adding Sb. As a result, <Γ> of the product plate can be reduced and good magnetic properties can be obtained. Here, when the amount of Sb added is less than 0.01 mass%, the effect of improving the texture is not recognized. On the other hand, if it exceeds 0.50 mass%, embrittlement and cold rolling become difficult. Therefore, it is preferable to set it as the range of 0.01-0.50 mass%.

Subsequently, at the time of recrystallization annealing, the temperature increase rate in a temperature range of 700 ° C or higher is set to a sequence of 100 ° C / h or lower, and reaching 750 ° C or higher and 1200 ° C or lower promotes grain growth and improves magnetic properties. Valid. When the temperature increase rate in the temperature range of 700 degreeC or more exceeds 100 degreeC / h, the improvement effect of a texture will become small. Therefore, it is preferable that the temperature increase rate be 100 degrees C / h or less. The lower limit of the temperature increase rate is not particularly determined, but if the temperature increase rate is less than 1 ° C./h, the annealing time is too long, which is economically disadvantageous. On the other hand, when the reached temperature in recrystallization annealing is less than 750 ° C., the grain growth is insufficient, so that the magnetic properties deteriorate. If it exceeds 1200 ° C, surface oxidation proceeds and iron loss deteriorates. Therefore, the temperature attained in recrystallization annealing is preferably 750 ° C or more and 1200 ° C or less. The crack time is not particularly determined. However, in order to obtain good iron loss, it is effective to promote grain growth by cracking for a long time within an economically acceptable range.

In addition, in order to significantly promote grain growth and improve the magnetic properties, in the first half of recrystallization annealing, a rapid heating of 2 ° C./s or more is performed between 500 to 700 ° C., the temperature is raised to 700 ° C. or more, and recrystallization is completed. After cooling to 700 degrees C or less, it is effective to sequence the temperature range of 700 degrees C or more again at 100 degrees C / h or less, and to reach the temperature of 750 degreeC or more and 1200 degrees C or less.

When the temperature is raised between 500 to 700 ° C. at less than 2 ° C./s throughout the recrystallization annealing, the effect of promoting grain growth in the second half of the recrystallization annealing is reduced. Therefore, it is preferable that the temperature increase between 500-700 degreeC in the whole recrystallization annealing shall be 2 degrees C / s or more. Similarly, even when the temperature reached in the first half of recrystallization annealing is lower than 750 ° C or higher than 1200 ° C, the effect of promoting grain growth in the latter annealing becomes small. Therefore, it is preferable to make the achieved temperature of recrystallization annealing propagation into 750-1200 degreeC. When the temperature rise in the second half of recrystallization annealing exceeds 100 ° C / h, the effect of improving the texture becomes small. Therefore, the preferable range of the temperature increase rate in the latter half of recrystallization annealing is 100 degrees C / h or less. If the temperature reached in the second half of recrystallization annealing is less than 750 ° C., grain growth is insufficient. If it exceeds 1200 ° C., surface oxidation proceeds, and magnetic properties deteriorate in any case. Therefore, it is preferable to make the arrival temperature of the latter half of recrystallization annealing into 750 degreeC or more and 1200 degrees C or less. The cracking time in the second half of recrystallization annealing is not particularly determined. However, in order to obtain good iron loss, it is effective to crack for a long time within an economically acceptable range and to promote grain growth.

Since the temperature rising up to 500 degreeC does not have a big influence on recrystallization behavior, it does not need to restrict in particular. In addition, the cooling conditions need not be particularly limited in terms of magnetic properties. However, economically, it is advantageous to set it as the range of 60 degreeC / min-10 degreeC / hr.

Moreover, Ni can be added in order to improve magnetic flux density. If the amount of Ni added is less than 0.01 mass%, the amount of improvement in magnetic properties is small. On the other hand, when the content exceeds 1.50 mass%, the development of aggregates is insufficient and the magnetic properties deteriorate. Therefore, the addition amount shall be 0.01-1.50 mass%.

Similarly, in order to improve iron loss, it is also effective to add Sn: 0.01-1.50 mass%, Cu: 0.01-1.50 mass%, P: 0.005-0.50 mass% and Cr: 0.01-1.50 mass%. If the amount added is less than this range, there is no iron loss improving effect, and if the amount added is large, the saturation magnetic flux density decreases.

In addition, the molten steel having the component of the present invention may be made into a slab by a usual ordinary ingot method and a continuous casting method, or a thin cast steel having a thickness of 100 mm or less may be produced by a direct casting method. The slabs are heated and hot rolled in a conventional manner. And it can also hot-roll immediately after a casting, without heating. In the case of a thin cast steel, hot rolling may be performed, or the hot rolling may be omitted, and the process may proceed to the subsequent step as it is. After hot rolling, hot-rolled sheet annealing is performed, and if necessary, one or more cold rolling including intermediate annealing is performed. After that, recrystallization annealing is performed, and insulation coating is performed as necessary. Finally, in order to improve the iron loss of the laminated steel sheet, an insulating coating is applied to the surface of the steel sheet. Coating may be a multilayer film which consists of two or more types of films, and what mixes resin etc. can also be performed.

In order to reduce P {111}, it is preferable that the average grain size before cold rolling before final cold rolling be 100 µm or more, and the rolling temperature of at least one pass in the final cold rolling step be 150 to 350 ° C or more. . Means for setting the average grain size before cold rolling to 100 μm or more include performing hot rolled sheet annealing and intermediate annealing at a high temperature of 1000 ° C. or higher, or means for performing cold rolling of 3-7% prior to hot rolled sheet annealing. There is this.

Example

Example 1

After manufacturing the steel slab of the component shown in Table 1 by continuous casting, the slab was heated at 1250 degreeC for 50 minutes, and it finished by 2.3 mm thickness by hot rolling. Hot-rolled sheet annealing was performed to the said hot-rolled sheet on the conditions of 1150 degreeC x 60 second, and was cooled between 150-400 degreeC to 150 degreeC / s. The annealing plate was cold rolled at 170 ° C. to finish with a final plate thickness of 0.35 mm. Subsequently, recrystallization annealing was performed at 1050 ° C. × 3 minutes in a hydrogen atmosphere, a semi-organic coating solution was applied, and baked at 300 ° C. to obtain a product.

From these product plates, ring-shaped samples having an outer diameter of 150 mm and an inner diameter of 100 mm were taken, and their magnetic properties were measured. Moreover, the orientation of the crystal grain in 10 mm x 10 mm each area | region of the product board surface was measured by EBSP, and << G> was computed. These measurement results were written together in Table 1. It can be seen that the steel sheet according to the present invention can obtain good magnetic properties.

Example 2

C: 38 ppm, Si: 3.24 mass%, Mn: 0.15 mass%, Al: 0.013 mass%, Sb: 0.02 mass%, S: 11 ppm, O: 7 ppm, N: 9 ppm and B: 2 ppm Then, a slab having a balance substantially composed of Fe was prepared by continuous casting. The slab was heated at 1150 ° C. for 30 minutes and finished to a thickness of 2.9 mm by hot rolling. Thereafter, the hot rolled sheet annealing was performed at 1050 ° C. for 60 seconds, cooled between 8 ° C./s between 800 ° C. and 400 ° C., and finished by cold rolling to a thickness of 0.35 mm. Subsequently, recrystallization annealing was carried out in a hydrogen atmosphere at a temperature rising rate shown in Table 2 to reach the maximum temperature, and then cooled. The inorganic coating liquid was apply | coated to the said annealing board, and it baked at 300 degreeC, and made into a product.

From these product plates, ring-shaped samples having an outer diameter of 150 mm and an inner diameter of 100 mm were taken, and their magnetic properties were measured. The orientation of the crystal grains in each of the 10 mm x 10 mm areas on the surface of the product plate was measured by EBSP to calculate <Γ>. These measurement results were written together in Table 2. Recrystallization annealing WHEREIN: The conditions which raise temperature to 700 degreeC from normal temperature to 200 degreeC / h, raise 700 degreeC or more to 1 to 100 degreeC / h on average, and reach | attain to the temperature of 750 degreeC or more and 1200 degrees C or less especially, It can be seen that a product having good magnetic properties can be obtained.

Example 3

A thin cast steel sheet having a thickness of 4.5 mm consisting of the same components as in Example 2 was produced by direct casting. Subsequently, hot-rolled sheet annealing was performed at 1150 degreeCx30 second, it cooled between 800-400 degreeC at 50 degreeC / s, and it was 1.6 mm thick by cold rolling at room temperature. After the intermediate annealing was performed on the cold rolled sheet for 1000 ° C. × 60 seconds, the sheet was finished to a thickness of 0.20 mm by cold rolling at room temperature. The cold-rolled sheet was subjected to primary and secondary recrystallization annealing under the conditions shown in Table 3 in an Ar atmosphere to obtain a product.

From these product plates, ring-shaped samples having an outer diameter of 150 mm and an inner diameter of 100 mm were taken, and their magnetic properties were measured. Moreover, the orientation of the crystal grain in each 10 mm x 10 mm area | region of the product board surface was measured by EBSP, and <Gi> was computed. These measurement results were written together in Table 3. In recrystallization annealing, it can be seen that a product having particularly good magnetic properties can be obtained by raising the temperature from 1 ° C to 100 ° C / h in a temperature range of 700 ° C or higher and reaching a temperature of 750 ° C or more and 1200 ° C or lower.

Example 4

After the slab of the component shown in Table 4 was manufactured by continuous casting, the slab was heated at 1200 degreeC for 50 minutes, and it finished by 2.6 mm thickness by hot rolling. The hot rolled sheet was subjected to hot rolled sheet annealing at 1180 ° C x 120 seconds, and cooled between 30 ° C and s between 800 and 400 ° C. The annealing plate was cold rolled at 150 ° C. to finish with a final plate thickness of 0.35 mm. The cold rolled sheet was subjected to recrystallization annealing at 1150 ° C. for 1 minute in an Ar atmosphere, and a semi-organic coating solution was applied and baked at 300 ° C. to obtain a product.

In this product plate, a ring-shaped sample having an outer diameter of 150 mm and an inner diameter of 100 mm was taken, and its magnetic properties were measured. Moreover, the orientation of the crystal grain in each 10 mm x 10 mm area | region of the product board surface was measured by EBSP, and <Gi> was computed. These measurement results were written together in Table 4. It can be seen that the steel sheet according to the present invention can obtain good magnetic properties.

Example 5

Slabs having the composition shown in Table 5 were prepared by continuous casting. Each slab was heated at 1150 ° C. for 20 minutes, and finished to a thickness of 2.8 mm by hot rolling. The hot rolled sheet was annealed to the hot rolled sheet at 1150 ° C. for 60 seconds. The annealing plate was cold rolled at 270 ° C. to finish with a final plate thickness of 0.35 mm. The cold rolled sheet was subjected to recrystallization annealing at 1050 ° C. for 2 minutes in a hydrogen atmosphere, a semi-organic coating solution was applied, and baked at 300 ° C. to obtain a product plate.

The magnetic properties (average of the L direction and the C direction) of the product plates thus obtained were measured. In addition, the orientation of the crystal grains in each 10 mm x 10 mm region of the surface was measured by EBSP, and the area ratio P {on the surface of the steel sheet surface of the crystal grains having a <Γ> and a crystal orientation is less than 15 degrees from the <111> axis. 111} was calculated.

In addition, the hardness and workability of the product sheet were also investigated. About workability, the product board was laminated | stacked to about 10 mm in height, 100 points of blood-closure processing of diameter: 30 mm was performed with the extrusion blanking machine, and the crack generation rate at that time was evaluated.

Moreover, it measured also about the average particle diameter after hot-rolled sheet annealing and a product board. The obtained results are written together in Table 5.

As can be seen from Table 5, when the component range of the present invention is satisfied, not only magnetic properties but also products having good processability can be obtained.

Example 6

C: 38 ppm, Si: 3.74 wt%, Mn: 0.35 wt%, Al: 0.013 wt%, S: 11 ppm, O: 7 ppm and N: 9 ppm, the balance being substantially of the composition of Fe Slabs were produced by continuous casting. This slab was heated at 1100 ° C. for 20 minutes and finished to a thickness of 3.2 mm by hot rolling. The hot rolled sheet was annealed to the hot rolled sheet at a temperature shown in Table 6 for 60 seconds. The annealing plate was subjected to cold rolling at the temperature shown in Table 6, and finished to a final plate thickness of 0.50 mm. Further, the cold rolled sheet was subjected to recrystallization annealing for 120 seconds at the temperature shown in Table 6, coated with an inorganic coating solution, and baked at 300 ° C. to obtain a product plate.

Table 6 shows the results of measurement of the magnetic properties, <Γ>, P {111}, hardness, workability, after annealing the hot plate and the average particle diameter of the product plate thus obtained.

As shown in Table 6, it can be seen that, by increasing the particle size before cold rolling and further increasing the rolling temperature, a product plate having particularly good magnetic properties and good workability can be obtained.

Example 7

The thin cast steel sheet (plate thickness: 4.5 mm) which becomes the component composition shown in Table 7 was manufactured by the direct casting method. After hot-rolled sheet annealing for 1150 degreeC and 60 second to this thin cast steel, it was made into the intermediate thickness of 1.2 mm by cold rolling at room temperature. The cold rolled sheet was subjected to intermediate annealing at 1000 ° C. for 60 seconds, and then finished by cold rolling at room temperature to a final plate thickness of 0.35 mm. Subsequently, recrystallization annealing was performed at 1025 ° C. for 5 minutes in an Ar atmosphere to obtain a product plate.

Table 8 shows the results of measurement of the magnetic properties, <Γ>, P {111}, hardness, workability and average particle diameter of the product sheet thus obtained.

As shown in Table 8, by producing using a component system satisfying the present invention, a product having good magnetic properties and workability can be obtained.

According to this invention, the non-oriented electrical steel sheet which has the outstanding magnetic flux density and iron loss which surpassed the magnetic characteristic obtained by the prior art can be obtained.

Claims (12)

A composition containing 1.5 to 8.0 mass% of Si and 0.005 to 2.50 mass% and suppressing the contents of C, S, N, O and B to 50 ppm or less, respectively, and is given by Formula (1). A non-oriented electrical steel sheet having a low iron loss and a high magnetic flux density having a crystal orientation parameter <Γ> of 0.200 or less. … (One) here, (u _ij , v _ij , w _ij ): 90 × i / (m−1) on the rolling surface from the rolling direction to the rolling perpendicular direction, where the crystal orientation is determined by crystal grains j represented by (hkl) <uvw>. ) I-th unit vector parallel to the inclined direction (i = 1,2… m, j = 1,2… n, u _ij ² + v _ij ² + w _ij ² = 1) v _j : the area ratio of crystallite j to the total measurement crystallite The non-aromatic method having low iron loss and high magnetic flux density according to claim 1, wherein the steel sheet has an area ratio of 20% or less on the surface of the steel sheet of the crystal grain having an average grain size of 50 to 500 µm and a crystal grain orientation of less than 15 degrees from the <111> axis. Electromagnetic steel sheet. The non-oriented electrical steel sheet according to claim 1 or 2, which further contains Al: 0.0010 to 0.10 mass% and has a <Γ> of 0.195 or less and has a low iron loss and a high magnetic flux density. The non-oriented electrical steel sheet according to any one of claims 1 to 3, which further contains Sb: 0.01 to 0.50 mass%, has a low iron loss and a high magnetic flux density. The method according to any one of claims 1 to 4, further comprising Ni: 0.01-3.50 mass%, Sn: 0.01-1.50 mass%, Cu: 0.01-1.50 mass%, P: 0.005-0.50 mass% and Cr: 0.01 A non-oriented electrical steel sheet containing at least one of -1.50 mass% and having a low iron loss and a high magnetic flux density. The slab is a molten steel containing 1.5 to 8.0 mass% of Si and 0.005 to 2.50 mass% of Mn, and the content of S, N, O and B is suppressed to 50 ppm or less, and the slab is hot rolled. Thereafter, after performing hot-rolled sheet annealing, cold rolling is carried out once or two or more times including intermediate annealing to finish the final sheet thickness, and then recrystallized annealing, and insulated coating as necessary. After adjusting the amount of C of the steel sheet to 50 ppm or less in any of the steps during melting or before recrystallization annealing, and performing hot-rolled sheet annealing at a temperature range of 800 to 1200 ° C, the temperature range of 800 to 400 ° C is 5 to 80 ° C. A method for producing a non-oriented electrical steel sheet having low iron loss and high magnetic flux density, which is cooled at / s. 7. The non-oriented method having low iron loss and high magnetic flux density according to claim 6, wherein the recrystallization annealing reaches a temperature range of not lower than 700 ° C but not higher than 100 ° C / h in a temperature range of 700 ° C or higher. Method of manufacturing an electronic steel sheet. The method of claim 6, wherein the recrystallization annealing is performed at a temperature range of 500 ° C to 700 ° C to 2 ° C / s or more, and is raised to 700 ° C or more to complete recrystallization, and then cooled to a temperature range of 700 ° C or less. The manufacturing method of the non-oriented electrical steel sheet with low iron loss and high magnetic flux density which make temperature rise in the temperature range of 700 degreeC or more again to 100 degreeC / h or less, and reaches to the temperature range of 750 degreeC or more and 1200 degrees C or less. The iron loss according to any one of claims 6 to 8, wherein the average crystal grain size before final cold rolling is set to 100 µm or more, and at least one pass of the final cold rolling is performed at a rolling temperature of 150 to 350 ° C. Moreover, the manufacturing method of the non-oriented electromagnetic steel sheet with high magnetic flux density. The method for producing a non-oriented electrical steel sheet according to any one of claims 6 to 9, wherein molten steel further contains 0.0010 to 0.10 mass% of Al. The method for producing a non-oriented electrical steel sheet according to any one of claims 6 to 10, wherein the molten steel further contains Sb: 0.01 to 0.50 mass%. 12. The molten steel further comprises Ni: 0.01-3.50 mass%, Sn: 0.01-1.50 mass%, Cu: 0.01-1.50 mass%, P: 0.005-0.50 mass% : A method for producing a non-oriented electrical steel sheet having low iron loss and high magnetic flux density, containing 0.01 to 1.50 mass% of at least one species.